How Do Eyeglass Lenses Work to Correct Your Vision?

different choices of eyeglasses
Photo by Francesco Paggiaro on

The question many people ask is – How do spectacles/glasses work? Some people think that they are the best option for vision correction. 

Both glasses and contacts to correct short-sightedness (myopia) and long-sightedness (hyperopia). These are eye problems which can be corrected by wearing glasses or contacts. And both glasses and contacts magnify light that goes into the eye by a different path, through the cornea, when the light is transmitted through the lenses or prisms.

The working of glasses depends on the types of spectacles worn, as well as the prescription of the wearer. For instance, it might seem that those who wear bifocals, which are a type of progressive lens, have their retina properly focused and therefore do not see any astigmatism or presbyopia. But, on the other hand, people with progressive lenses and those who wear toric lenses are likely to experience some degree of astigmatism or presbyopia.

Astigmatism occurs when the curvature of the eye’s cornea is slightly irregular, causing light to reflect in certain directions. This occurs even when the patient has nearsightedness or farsightedness. Presbyopia, on the other hand, occurs when the patient has nearsightedness or farsightedness and experiences blurred vision. When the patient wears glasses, the curvature of the lens will be curved in the same direction. However, if the patient wears a pair of progressive lenses, the lens’ axis of curvature will be slightly bent so that it reflects light coming from all directions and sharpen up images that are seen with short-sightedness or hyperopia. The result is that the vision of the wearer is improved.

It was found that a solution called Hydrostatic is used in the manufacture of most spectacles because of this bending ability of the lens. The Hydrostatic process was developed by German optical engineers during World War I. The first modern day hydrostatic apparatus was created in 1923. A cylindrical lens is used for the manufacture of most spectacles because of the hydrostatic feature.

The length of a dioptre is the distance between the center of the cylinder and the lowest point of the lens. In a normal pair of glasses, the distance between the top and bottom of the frame is the dioptres. The dioptres refers to the angle formed between the rays coming from the two upper ends of the cylinder. This angle is measured in radians.

Spectacles have a practical role in society as they are able to filter and control the natural light. The filtering function of spectacles is beneficial for people who need high levels of visibility but do not want their gaze or their presence known to others. High levels of visibility as provided by spectacles helps them carry out their professional and social media roles comfortably. They are also essential for those who have difficulty seeing clearly or who are unable to see due to cataract, presbyopia or retinal detachment.


Glasses correct vision by allowing your eyes to focus light on the correct spot of your retina. The curved frames bend light, and with the right prescription, these frames manipulate the light to reach the correct spot on your retina. The result is a clear, crisp image. Eyeglass lenses attempt to correct problems, and place the focal point where it needs to be — on your retina. A lens is just two prisms put together back to back.

Glasses or contact lenses correct vision because they allow the eye to focus light in the right spot on the retina — the spot that produces the clearest image. Because everyone’s eyes are different, a pair of glasses that makes one person see wonderfully may look terribly blurry to someone else.

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